But even if SEC officials manage to dodge criminal charges, it won't change what happened: The nation's top financial police destroyed more than a decade's worth of intelligence they had gathered on some of Wall Street's most egregious offenders.

But we're equally in the dark about another hypothetical. Forget about what might have been if the SEC had followed up in earnest on all of those lost MUIs. What if even a handful of them had turned into real cases? How many investors might have been saved from crushing losses if Lehman Brothers had been forced to reveal its shady accounting way back in 2002? Might the need for taxpayer bailouts have been lessened had fraud cases against Citigroup and Bank of America been pursued in 2005 and 2007? And would the U.S. government have doubled down on its bailout of AIG if it had known that some of the firm's executives were suspected of insider trading in September 2008?

Imagine a world in which a man who is repeatedly investigated for a string of serious crimes, but never prosecuted, has his slate wiped clean every time the cops fail to make a case. No more Lifetime channel specials where the murderer is unveiled after police stumble upon past intrigues in some old file - "Hey, chief, didja know this guy had two wives die falling down the stairs?" No more burglary sprees cracked when some sharp cop sees the same name pop up in one too many witness statements. This is a different world, one far friendlier to lawbreakers, where even the suspicion of wrongdoing gets wiped from the record.